Add required TFERACTION to TRANSFER

[oyarzun]

This PR adds support for TFERACTION in a TRANSFER transaction.

The OFX specification requires that a TRANSFER transaction has a TFERACTION element to designates if the transaction is IN or OUT of the account.

 <xsd:complexType name="Transfer">
  <xsd:annotation>
   <xsd:documentation>
        The OFX element "TRANSFER" is of type "Transfer"
      </xsd:documentation>
  </xsd:annotation>
  <xsd:complexContent>
   <xsd:extension base="ofx:AbstractInvestmentTransaction">
    <xsd:sequence>
     <xsd:element name="SECID" type="ofx:SecurityId"/>
     <xsd:element name="SUBACCTSEC" type="ofx:SubAccountEnum"/>
     <xsd:element name="UNITS" type="ofx:QuantityType"/>
     <xsd:element name="TFERACTION" type="ofx:InOutEnum"/>
     <xsd:element name="POSTYPE" type="ofx:PositionTypeEnum"/>
     <xsd:element name="INVACCTFROM" type="ofx:InvestmentAccount" minOccurs="0"/>
     <xsd:element name="AVGCOSTBASIS" type="ofx:AmountType" minOccurs="0"/>
     <xsd:element name="UNITPRICE" type="ofx:UnitPriceType" minOccurs="0"/>
     <xsd:element name="DTPURCHASE" type="ofx:DateTimeType" minOccurs="0"/>
     <xsd:element name="INV401KSOURCE" type="ofx:Investment401kSourceEnum" minOccurs="0"/>
    </xsd:sequence>
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

[coveralls]

coverage: 95.238% (+0.02%) from 95.215%
when pulling 63e4944 on oyarzun:transfer-action-support
into 1eb1d9a on kedder:master.

[kedder]

Thanks @oyarzun! I can release the new version if you want.